Draft Impervious Cover Assessment for Fair Haven Borough, Monmouth County, New Jersey

Transcription

1 Draft Impervious Cover Assessment for Fair Haven Borough, Monmouth County, New Jersey Prepared for Fair Haven Borough by the Rutgers Cooperative Extension Water Resources Program March 15, 2016

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3 Introduction Pervious and impervious are terms that are used to describe the ability or inability of water to flow through a surface. When rainfall hits a surface, it can soak into the surface or flow off the surface. Pervious surfaces are those which allow stormwater to readily soak into the soil and recharge groundwater. When rainfall drains from a surface, it is called "stormwater" runoff (Figure 1). An impervious surface can be any material that has been placed over soil that prevents water from soaking into the ground. Impervious surfaces include paved roadways, parking lots, sidewalks, and rooftops. As impervious areas increase, so does the volume of stormwater runoff. Figure 1: Stormwater draining from a parking lot New Jersey has many problems due to stormwater runoff, including: Pollution: According to the 2010 New Jersey Water Quality Assessment Report, 90% of the assessed waters in New Jersey are impaired, with urban-related stormwater runoff listed as the most probable source of impairment (USEPA, 2013). As stormwater flows over the ground, it picks up pollutants including animal waste, excess fertilizers, pesticides, and other toxic substances. These pollutants are then able to enter waterways. Flooding: Over the past decade, the state has seen an increase in flooding. Communities around the state have been affected by these floods. The amount of damage caused also has increased greatly with this trend, costing billions of dollars over this time span. 1

4 Erosion: Increased stormwater runoff causes an increase in the velocity of flows in our waterways. The increased velocity after storm events erodes stream banks and shorelines, degrading water quality. This erosion can damage local roads and bridges and cause harm to wildlife. The primary cause of the pollution, flooding, and erosion problems is the quantity of impervious surfaces draining directly to local waterways. New Jersey is one of the most developed states in the country. Currently, the state has the highest percent of impervious cover in the country at 12.1% of its total area (Nowak & Greenfield, 2012). Many of these impervious surfaces are directly connected to local waterways (i.e., every drop of rain that lands on these impervious surfaces ends up in a local river, lake, or bay without any chance of being treated or soaking into the ground). To repair our waterways, reduce flooding, and stop erosion, stormwater runoff from impervious surfaces has to be better managed. Surfaces need to be disconnected with green infrastructure to prevent stormwater runoff from flowing directly into New Jersey's waterways. Disconnection redirects runoff from paving and rooftops to pervious areas in the landscape. Green infrastructure is an approach to stormwater management that is cost-effective, sustainable, and environmentally friendly. Green infrastructure projects capture, filter, absorb, and reuse stormwater to maintain or mimic natural systems and to treat runoff as a resource. As a general principal, green infrastructure practices use soil and vegetation to recycle stormwater runoff through infiltration and evapotranspiration. When used as components of a stormwater management system, green infrastructure practices such as bioretention, green roofs, porous pavement, rain gardens, and vegetated swales can produce a variety of environmental benefits. In addition to effectively retaining and infiltrating rainfall, these technologies can simultaneously help filter air pollutants, reduce energy demands, mitigate urban heat islands, and sequester carbon while also providing communities with aesthetic and natural resource benefits (USEPA, 2013). The first step to reducing the impacts from impervious surfaces is to conduct an impervious cover assessment. This assessment can be completed on different scales: individual lot, municipality, or watershed. Impervious surfaces need to be identified for stormwater management. Once impervious surfaces have been identified, there are three steps to better manage these surfaces. 2

5 1. Eliminate surfaces that are not necessary. For example, a paved courtyard at a public school could be converted to a grassed area. 2. Reduce or convert impervious surfaces. There may be surfaces that are required to be hardened, such as roadways or parking lots, but could be made smaller and still be functional. A parking lot that has two-way car ways could be converted to one-way car ways. There also are permeable paving materials such as porous asphalt, pervious concrete, or permeable paving stones that could be substituted for impermeable paving materials (Figure 2). 3. Disconnect impervious surfaces from flowing directly to local waterways. There are many ways to capture, treat, and infiltrate stormwater runoff from impervious surfaces. Opportunities may exist to reuse this captured water. Figure 2: Rapid infiltration of water through porous pavement is demonstrated at the USEPA Edison New Jersey test site 3

6 Fair Haven Borough Impervious Cover Analysis Located in Monmouth County in central New Jersey, Fair Haven Borough covers approximately 4.17 square miles west of Red Bank. Figures 3 and 4 illustrate that Fair Haven Borough is dominated by urban land uses. A total of 69.2% of the municipality s land use is classified as urban. Of the urban land in Fair Haven Borough, medium density residential is the dominant land use (Figure 5). The literature suggests a link between impervious cover and stream ecosystem impairment starting at approximately 10% impervious surface cover (Schueler, 1994; Arnold and Gibbons, 1996; May et al., 1997). Impervious cover may be linked to the quality of lakes, reservoirs, estuaries, and aquifers (Caraco et al., 1998), and the amount of impervious cover in a watershed can be used to project the current and future quality of streams. Based on the scientific literature, Caraco et al. (1998) classified urbanizing streams into the following three categories: sensitive streams, impacted streams, and non-supporting streams. Sensitive steams typically have a watershed impervious surface cover from 0 10%. Impacted streams have a watershed impervious cover ranging from 11-25% and typically show clear signs of degradation from urbanization. Nonsupporting streams have a watershed impervious cover of greater than 25%; at this high level of impervious cover, streams are simply conduits for stormwater flow and no longer support a diverse stream community. The New Jersey Department of Environmental Protection s (NJDEP) 2007 land use/land cover geographical information system (GIS) data layer categorizes Fair Haven Borough into many unique land use areas, assigning a percent impervious cover for each delineated area. These impervious cover values were used to estimate the impervious coverage for Fair Haven Borough. Based upon the 2007 NJDEP land use/land cover data, approximately 27.3% of Fair Haven Borough has impervious cover. This level of impervious cover suggests that the streams in Fair Haven Borough are likely non-supporting streams. 4

7 Wetlands 3.7% Barren Land 0.4% Forest 2.5% Water 24.2% Urban 69.2% Figure 3: Pie chart illustrating the land use in Fair Haven Borough 5

8 Figure 4: Map illustrating the land use in Fair Haven Borough 6

9 Recreational Land 3.6% Mixed Urban 0.9% Rural Residential 15.0% Commercial 5.3% Low Density Residential 14.0% Medium Density Residential 61.2% Figure 5: Pie chart illustrating the various types of urban land use in Fair Haven Borough 7

10 Water resources are typically managed on a watershed/subwatershed basis; therefore an impervious cover analysis was performed for each Raritan River subwatershed within Fair Haven Borough (Table 1 and Figure 6). On a subwatershed basis, impervious cover ranges from 15.0% in the Shrewsbury River subwatershed to 27.6% in the Navesink River subwatershed. Evaluating impervious cover on a subwatershed basis allows the municipality to focus impervious cover reduction or disconnection efforts in the subwatersheds where frequent flooding occurs. In developed landscapes, stormwater runoff from parking lots, driveways, sidewalks, and rooftops flows to drainage pipes that feed the sewer system. The cumulative effect of these impervious surfaces and thousands of connected downspouts reduces the amount of water that can infiltrate into soils and greatly increases the volume and rate of runoff that flows to waterways. Stormwater runoff volumes (specific to Fair Haven Borough, Monmouth County) associated with impervious surfaces were calculated for the following storms: the New Jersey water quality design storm of 1.25 inches of rain, an annual rainfall of 44 inches, the 2-year design storm (3.4 inches of rain), the 10-year design storm (5.2 inches of rain), and the 100-year design storm (8.9 inches of rain). These runoff volumes are summarized in Table 2. A substantial amount of rainwater drains from impervious surfaces in Franklin Township. For example, if the stormwater runoff from one water quality storm (1.25 inches of rain) in the Navesink River subwatershed was harvested and purified, it could supply water to 169 homes for one year 1. 1 Assuming 300 gallons per day per home 8

11 Table 1: Impervious cover analysis by subwatershed for Fair Haven Borough Subwatershed Total Area Land Use Area Water Area Impervious Cover (ac) (mi 2 ) (ac) (mi 2 ) (ac) (mi 2 ) (ac) (mi 2 ) (%) Navesink River 2, , % Shrewsbury River % Total 2, , % 9

12 Figure 6: Map of the subwatersheds in Fair Haven Borough 10

13 Table 2: Stormwater runoff volumes from impervious surfaces by subwatershed in Fair Haven Borough Subwatershed Navesink River Shrewsbury River Total Runoff Volume for the 1.25" NJ Water Quality Storm (Mgal) Total Runoff Volume for the NJ Annual Rainfall of 44" (Mgal) Total Runoff Volume for the 2-Year Design Storm (3.4") (Mgal) Total Runoff Volume for the 10-Year Design Storm (5.2") (Mgal) Total Runoff Volume for the 100-Year Design Storm (8.9") (Mgal) Total

14 The next step is to set a reduction goal for impervious area in each subwatershed. Based upon the Rutgers Cooperative Extension (RCE) Water Resources Program's experience, a 10% reduction would be a reasonably achievable reduction for these subwatersheds in Fair Haven Borough. While it may be difficult to eliminate paved areas or replace paved areas with permeable pavement, it is relatively easy to identify impervious surfaces that can be disconnected using green infrastructure practices. For all practical purposes, disconnecting an impervious surface from a storm sewer system or a water body is an "impervious area reduction." The RCE Water Resources Program recommends that all green infrastructure practices that are installed to disconnect impervious surfaces should be designed for the 2-year design storm (3.4 inches of rain over 24- hours). Although this results in management practices that are slightly over-designed by NJDEP standards, which require systems to be designed for the New Jersey water quality storm (1.25 inches of rain over 2-hours), these systems will be able to handle the increase in storm intensities that are expected to occur due to climate change. By designing these management practices for the 2-year design storm, these practices will be able to manage 95% of the annual rainfall volume. The recommended annual reductions in runoff volumes are shown in Table 3. As previously mentioned, once impervious surfaces have been identified, the next steps for managing impervious surfaces are to 1) eliminate surfaces that are not necessary, 2) reduce or convert impervious surfaces to pervious surfaces, and 3) disconnect impervious surfaces from flowing directly to local waterways. Elimination of Impervious Surfaces One method to reduce impervious cover is to "depave." Depaving is the act of removing paved impervious surfaces and replacing them with pervious soil and vegetation that will allow for the infiltration of rainwater. Depaving leads to the re-creation of natural space that will help reduce flooding, increase wildlife habitat, and positively enhance water quality as well as beautify neighborhoods. Depaving also can bring communities together around a shared vision to work together to reconnect their neighborhood to the natural environment. 12

15 Table 3: Impervious cover reductions by subwatershed in Fair Haven Borough Subwatershed Recommended Impervious Area Reduction (10%) (ac) Annual Runoff Volume Reduction 2 (MGal) Navesink River Shrewsbury River Total Annual Runoff Volume Reduction = Acres of IC x 43,560 ft 2 /ac x 44 in x (1 ft/12 in) x 0.95 x (7.48 gal/ft 3 ) x (1 MGal/1,000,000 gal) All BMPs should be designed to capture the first 3.4 inches of rain from each storm. This would allow the BMP to capture 95% of the annual rainfall of 44 inches. 13

16 Pervious Pavement There are four different types of permeable pavement systems that are commonly being used throughout the country to reduce the environmental impacts from impervious surfaces. These surfaces include pervious concrete, porous asphalt, interlocking concrete pavers, and grid pavers. Permeable pavement is a stormwater drainage system that allows rainwater and runoff to move through the pavement s surface to a storage layer below, with the water eventually seeping into the underlying soil. Permeable pavement is beneficial to the environment because it can reduce stormwater volume, treat stormwater water quality, replenish the groundwater supply, and lower air temperatures on hot days (Rowe, 2012). Permeable surfaces: (A) pervious concrete, (B) porous asphalt, (C) interlocking concrete pavers, (D) grid pavers (Rowe, 2012) Pervious concrete and porous asphalt are the most common of the permeable surfaces. They are similar to regular concrete and asphalt but without the fine materials. This allows water to quickly pass through the material into an underlying layered system of stone that holds the water allowing it to infiltrate into the underlying uncompacted soil. Impervious Cover Disconnection Practices By redirecting runoff from paving and rooftops to pervious areas in the landscape, the amount of directly connected impervious area in a drainage area can be greatly reduced. There are many cost-effective ways to disconnect impervious surfaces from local waterways. Simple Disconnection: This is the easiest and least costly method to reduce stormwater runoff for smaller storm events. Instead of piping rooftop runoff to the street where it enters the catch basin and is piped to the river, the rooftop runoff is released onto a grassed 14

17 area to allow the water to be filtered by the grass and soak into the ground. A healthy lawn typically can absorb the first one to two inches of stormwater runoff from a rooftop. Simple disconnection also can be used to manage stormwater runoff from paved areas. Designing a parking lot or driveway to drain onto a grassed area, instead of the street, can dramatically reduce pollution and runoff volumes. Rain Gardens: Stormwater can be diverted into shallow landscaped depressed areas (i.e., rain gardens) where the vegetation filters the water, and it is allowed to soak into the ground. Rain gardens, also known as bioretention systems, come in all shapes and sizes and can be designed to disconnect a variety of impervious surfaces (Figure 7). Figure 7: Rain garden outside the RCE of Gloucester County office which was designed to disconnect rooftop runoff from the local storm sewer system Rainwater Harvesting: Rainwater harvesting includes the use of rain barrels and cisterns (Figures 8a and 8b). These can be placed below downspouts to collect rooftop runoff. The collected water has a variety of uses including watering plants and washing cars. This practice also helps cut down on the use of potable water for nondrinking purposes. It is important to divert the overflow from the rainwater harvesting system to a pervious area. 15

18 Figure 8a: Rain barrel used to disconnect a downspout with the overflow going to a flower bed Figure 8b: A 5,000 gallon cistern used to disconnect the rooftop of the Department of Public Works in Clark Township to harvest rainwater for nonprofit car wash events 16

19 Examples of Opportunities in Fair Haven Borough To address the impact of stormwater runoff from impervious surfaces, the next step is to identify opportunities in the municipality for eliminating, reducing, or disconnecting directly connected impervious surfaces. To accomplish this task, an impervious cover reduction action plan should be prepared. Aerial photographs are used to identify sites with impervious surfaces in the municipality that may be suitable for inclusion in the action plan. After sites are identified, site visits are conducted to photo-document all opportunities and evaluate the feasibility of eliminating, reducing or disconnecting directly connected impervious surfaces. A brief description of each site discussing the existing conditions and recommendations for treatment of the impervious surfaces is developed. After a number of sites have been selected for inclusion in the action plan, concept plans and detailed green infrastructure information sheets are prepared for a selection of representative sites. For Fair Haven Borough, three sites have been included in this assessment. Examples of concept plans and detailed green infrastructure information sheets are provided in Appendix A. The detailed green infrastructure information sheets describe existing conditions and issues, proposed solutions, anticipated benefits, possible funding sources, potential partners and stakeholders, and estimated costs. Additionally, each project has been classified as a mitigation opportunity for recharge potential, total suspended solids removal, and stormwater peak reduction. Finally, these detailed green infrastructure information sheets provide an estimate of gallons of stormwater captured and treated per year by each proposed green infrastructure practice. The concept plans provide an aerial photograph of the site and details of the proposed green infrastructure practices. Conclusions Fair Haven Borough can reduce flooding and improve its waterways by better managing stormwater runoff from impervious surfaces. This impervious cover assessment is the first step toward better managing stormwater runoff. The next step is to develop an action plan to eliminate, reduce, or disconnect impervious surfaces where possible and practical. Many of the highly effective disconnection practices are inexpensive. The entire community can be engaged in implementing these disconnection practices. 17

20 References Arnold, C.L. Jr. and C.J. Gibbons Impervious Surface Coverage The Emergence of a Key Environmental Indicator. Journal of the American Planning Association 62(2): Caraco, D., R. Claytor, P. Hinkle, H. Kwon, T. Schueler, C. Swann, S. Vysotsky, and J. Zielinski Rapid Watershed Planning Handbook. A Comprehensive Guide for Managing Urbanizing Watersheds. Prepared by Center For Watershed Protection, Ellicott City, MD. Prepared for U.S. Environmental Protection Agency, Office of Wetlands, Oceans and Watersheds and Region V. October May, C.W., R.R. Horner, J.R. Karr, B.W. Mar, E.G. Welch Effects of Urbanization on Small Streams in the Puget Sound Lowland Ecoregion. Watershed Protection Techniques 2(4): Nowak, D. J., and E. J. Greenfield, Trees and Impervious Cover in the United States. Landscape and Urban Planning 107 (2012): Rowe, A., Green Infrastructure Practices: An Introduction to Permeable Pavement. Rutgers NJAES Cooperative Extension, FS1177, pp Schueler, T The Importance of Imperviousness. Watershed Protection Techniques1(3): United States Environmental Protection Agency (USEPA), Watershed Assessment, Tracking, and Environmental Results, New Jersey Water Quality Assessment Report. 18

21 Appendix A Examples of Impervious Cover Reduction Action Plan Projects Concept Plans and Detailed Green Infrastructure Information Sheets

22 Fair Haven Township Impervious Cover Assessment Fair Haven Police Department, 35 Fisk Street PROJECT LOCATION: SITE PLAN: A C 1 A B 2 1 BIORETENTION SYSTEMS: Rooftop runoff from the building can be captured, treated, and infiltrated by installing a bioretention system. Bioretention systems can reduce sediment and nutrient loading to the local waterway while providing beautiful landscaping. 2 POROUS PAVEMENTS: A section of the parking lot can be converted to porous pavement. This can allow runoff from the parking lot to infiltrate into the ground reducing the volume that enters the catch basin at the end of the driveway. 1 BIORETENTION SYSTEM 2 POROUS PAVEMENT C

23 Fair Haven Police Department Green Infrastructure Information Sheet Location: 35 Fisk Street Fair Haven, NJ Green Infrastructure Description: bioretention system (rain garden) pervious pavement Mitigation Opportunities: recharge potential: yes stormwater peak reduction potential: yes TSS removal potential: yes Municipality: Fair Haven Township Subwatershed: Navesink River Targeted Pollutants: total nitrogen (TN), total phosphorous (TP), and total suspended solids (TSS) in surface runoff Stormwater Captured and Treated Per Year: rain garden: 17,197 gal. pervious pavement: 130,433 gal. Existing Conditions and Issues: There are impervious surfaces on this site that contribute to stormwater runoff and nonpoint source pollution. Runoff is carrying nonpoint source pollution directly to the sewer system, adding pressure on the sewer system. Proposed Solution(s): Converting parking spaces to porous pavement will help manage stormwater runoff on the site. A bioretention system or rain garden could be installed in the back of the building to capture, treat, and infiltrate runoff from the roof. Anticipated Benefits: A bioretention system is estimated to achieve a 30% removal rate for TN and a 60% removal rate for TP (NJDEP BMP Manual). TSS loadings may be reduced by up to 90%. If the bioretention system is designed to capture and infiltrate stormwater runoff from the 2-year design storm (3.3 inches of rain over 24 hours), it will prevent approximately 95% of the TN, TP, and TSS from flowing directly into local waterways. A bioretention system would also provide ancillary benefits such as enhanced wildlife and aesthetic appeal to faculty and students. Porous pavement parking spaces are estimated to achieve a 50% removal rate for TN and a 60% removal rate for TP (NJDEP BMP Manual). TSS loadings may be reduced by up to 80%. If the porous pavement parking spaces are designed to capture and infiltrate stormwater runoff from the 2-year design storm (3.4 inches of rain over 24 hours), these systems will prevent approximately 95% of the TN, TP, and TSS from flowing directly into local waterways. Possible Funding Sources: Mitigation funds from local developers NJDEP grant programs Fair Haven Township Partners/Stakeholders: Rutgers Cooperative Extension Boy Scouts, Girl Scouts, or service project

24 Fair Haven Police Department Green Infrastructure Information Sheet Estimated Cost: The rain garden would need to be approximately 165 square feet. At $5 per square foot, the estimated cost of the rain garden is $825. The porous pavement would need to be approximately 1,670 square feet. At $20 per square foot, the estimated cost of the porous pavement is $33,400. The total cost of the project would be approximately $34,225.

25 Fair Haven Township Impervious Cover Assessment Fair Haven Volunteer Fire Company, 645 River Road PROJECT LOCATION: SITE PLAN: A C B A B BIORETENTION SYSTEMS: A bioretention system can be installed in the turf grass off the east corner of the building to capture, treat, and infiltrate runoff from the rooftop and parking lot. The bioretention system can also provide habitat for birds, butterflies, and pollinators. C RAINWATER HARVESTING SYSTEMS: A cistern can capture a portion of the stormwater runoff from the building s rooftop. Harvesting the runoff will allow the stormwater to be used for washing emergency vehicles. BIORETENTION SYSTEM 2 RAINWATER HARVESTING SYSTEM

26 Fair Haven Volunteer Fire Company Green Infrastructure Information Sheet Location: 645 River Road Fair Haven, NJ Green Infrastructure Description: bioretention system (rain garden) rainwater harvesting system Municipality: Fair Haven Township Subwatershed: Navesink River Targeted Pollutants: total nitrogen (TN), total phosphorous (TP), and total suspended solids (TSS) in surface runoff Mitigation Opportunities: recharge potential: yes stormwater peak reduction potential: yes TSS removal potential: yes Stormwater Captured and Treated Per Year: rain garden: 154,795 gal. rainwater harvesting systems: 14,946 gal. Existing Conditions and Issues: There are impervious surfaces on this site that contribute to stormwater runoff and nonpoint source pollution. Downspouts on the building are directly connected to the storm sewer system, adding pressure on the system. At the time of the assessment the parking lot was in good condition. Proposed Solution(s): A bioretention system or rain garden could be installed in the turf grass east to the building to capture, treat, and infiltrate runoff from the nearby downspout by disconnecting and redirecting it and the parking lot. Additionally, a cistern can be installed to harvest rainwater from roof. The water can be used to wash vehicles on site. Anticipated Benefits: A bioretention system is estimated to achieve a 30% removal rate for TN and a 60% removal rate for TP (NJDEP BMP Manual). TSS loadings may be reduced by up to 90%. If the bioretention system is designed to capture and infiltrate stormwater runoff from the 2-year design storm (3.3 inches of rain over 24 hours), it will prevent approximately 95% of the TN, TP, and TSS from flowing directly into local waterways. A bioretention system would also provide ancillary benefits such as enhanced wildlife and aesthetic appeal to faculty and students. The rainwater harvesting system (the cistern) would be designed to capture the first 1.25 inches of rain, it would reduce the pollutant loading by 90% during the periods when it is operational (i.e., it would not be used in the winter when there is a chance of freezing). Possible Funding Sources: Mitigation funds from local developers NJDEP grant programs Residents

27 Partners/Stakeholders: Fair Haven Township Rutgers Cooperative Extension Boy Scouts, Girl Scouts, or service project Fair Haven Volunteer Fire Company Green Infrastructure Information Sheet Estimated Cost: The rain garden would need to be approximately 1,490 square feet. At $5 per square foot, the estimated cost of the rain garden is $7,450. The rainwater harvesting cistern would need to be approximately 1,000 gallons. The approximate cost of a cistern this size is $2,000. The total cost of the project would be approximately $9,450.

28 Fair Haven Township Impervious Cover Assessment Church of the Nativity, 180 Ridge Road PROJECT LOCATION: A SITE PLAN: A B 1 C B 1 BIORETENTION SYSTEMS: A bioretention system can be installed off the northern side of the building to intercept runoff where it can be treated and allowed to infiltrate. The rain garden can also provide habitat for birds, butterflies, and pollinators. C 1 BIORETENTION SYSTEM RESTRICTIVE SOILS IN THIS REGION - Site specific soil testing must be conducted. - Green infrastructure in this area may require underdrain systems.

29 Church of the Nativity Green Infrastructure Information Sheet Location: 180 Ridge Road Rumson, NJ Green Infrastructure Description: bioretention system (rain garden) Mitigation Opportunities: recharge potential: yes stormwater peak reduction potential: yes TSS removal potential: yes Municipality: Fair Haven Borough Subwatershed: Navesink River Targeted Pollutants: total nitrogen (TN), total phosphorous (TP), and total suspended solids (TSS) in surface runoff Stormwater Captured and Treated Per Year: rain garden: 69,047 gal. Existing Conditions and Issues: There are impervious surfaces on this site that contribute to stormwater runoff and nonpoint source pollution. Runoff is carrying nonpoint directly to the sewer system, adding pressure on the sewer system and carrying with it pollutants from the rooftop. Proposed Solution(s): A bioretention system or rain garden could be installed in the turf grass in the north of the building to capture, treat, and infiltrate runoff overflow from the pavement. Anticipated Benefits: A bioretention system is estimated to achieve a 30% removal rate for TN and a 60% removal rate for TP (NJDEP BMP Manual). TSS loadings may be reduced by up to 90%. If the bioretention system is designed to capture and infiltrate stormwater runoff from the 2-year design storm (3.3 inches of rain over 24 hours), these systems will prevent approximately 95% of the TN, TP, and TSS from flowing directly into local waterways. A bioretention system would also provide ancillary benefits such as enhanced wildlife and aesthetic appeal to faculty and students. Possible Funding Sources: Mitigation funds from local developers NJDEP grant programs Boy Scouts, Girl Scouts, or service project Partners/Stakeholders: Fair Haven Borough Rutgers Cooperative Extension Estimated Cost: The rain garden would need to be approximately 660 square feet. At $5 per square foot, the estimated cost of the rain garden is $3,300.